Correct option is B
The correct answer is (b) Reversible process
Explanation:
A Daniell cell involves a redox reaction between zinc and copper electrodes in their respective sulfate solutions, where:
- Zn(s) → Zn²⁺(aq) + 2e⁻ (oxidation at anode)
- Cu²⁺(aq) + 2e⁻ → Cu(s) (reduction at cathode)
This electrochemical reaction can proceed in both directions under suitable conditions, meaning that the products can be converted back into reactants by reversing the current. Hence, the phase change (solid metal to ion and vice versa) is part of a reversible process.
Information Booster:
- A reversible process is one that can be reversed by an infinitesimal change in a variable (like pressure, temperature, or voltage) and the system remains in equilibrium throughout the process.
- In electrochemical cells like the Daniell cell, the reaction can be reversed by applying an external voltage greater than the cell potential, turning the cell into an electrolytic cell.
Additional Knowledge:
Isochoric Process (Constant Volume Process)
- Definition: A thermodynamic process in which the volume remains constant.
- Since volume doesn’t change, no work is done (W = 0).
- Heat added to the system increases the internal energy and temperature.
- Example: Heating a gas in a sealed rigid container.
- Key Equation: Q=ΔU
(Because W=0, all the heat goes into internal energy.)
Cyclic Process
- Definition: A process in which a system returns to its initial state after undergoing a series of changes.
- In a full cycle:
- Change in internal energy (ΔU) = 0
- Net heat supplied (Q) = Net work done (W)
Key Point: Q=W
- Common in heat engines like the Carnot cycle or Otto cycle.
Irreversible Process
- Definition: A process that cannot be reversed without leaving a permanent change in the system or surroundings.
- It involves friction, unrestrained expansion, sudden pressure changes, or heat loss.
- Less efficient than reversible processes.
- Real-world processes are mostly irreversible.
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